Evidence of P-body-like structures in Trypanosoma cruzi.

Gene expression in trypanosomatids is mainly regulated post-transcriptionally. One of the mechanisms involves the differential stability of mRNAs. However, the existence of other mechanisms involving the accessibility of mRNAs to the translation machinery cannot be ruled out. Defined cytoplasmic foci containing non-translating mRNPs, known as P-bodies, have been discovered in recent years. P-bodies are sites where mRNA can be decapped and 5'-3' degraded or stored for subsequent return to polysomes. The highly conserved DEAD box helicase Dhh1p is a marker protein of P-body functions. Here, we report the identification and cloning of a Trypanosoma cruzi Dhh1 homolog gene. TcDhh1 expression is not regulated through the parasite life cycle or under stress conditions. We show that TcDhh1 is present in polysome-independent complexes and is localized to discrete cytoplasmic foci, resembling P-bodies; these foci vary in number according to nutritional stress conditions and cycloheximide/puromycin treatment.